Amino acid balancing to minimize N excretion

Dairy producers and nutritionists face a variety of challenges today with rising input costs and greater regulation than ever before. Stringent environmental regulation has become an ever-increasing concern for dairy producers in areas like the Chesapeake Bay watershed and California, with limited tools available to help ensure requirements are met.

“In the past overfeeding protein was a common practice, especially when the ingredient was inexpensive,” explains Elliot Block, PhD, Arm & Hammer Animal Nutrition. “This is, however, not an ideal solution, because excess protein is excreted by the cow into the environment, and energy must be diverted to excrete extra protein rather than be used for greater production. This ultimately increases ration costs without generating additional return for the producer.”

The practice of amino acid balancing aims to ensure optimal levels of lysine and methionine—the two most limiting amino acids—are delivered to the small intestine to enhance protein synthesis. Both amino acids cannot be produced by the cow or from other amino acids, so they must be delivered through the diet. Bypass forms of these amino acids are critical to ensure optimal levels are available for protein production and efficient nutrient utilization.

Amino acid balancing is effective Research from Pennsylvania State University1 confirms balancing rations for metabolizable protein and amino acids instead of crude protein can reduce nitrogen excretion while improving milking herd performance. The research was conducted on the university dairy, where the lactating ration was reformulated with lower crude protein (16%) and a similar amino acid profile. Performance was compared to herd historical data, when diets were balanced for 18% protein. Following ration reformulation the herd experienced positive results, including:

More milk and component production. Cows produced an additional 6 lbs. of milk, increasing from 78 lbs. to 84 lbs. Component levels climbed as well.

Greater nitrogen efficiency. Nitrogen efficiency improved by 4.6% over the herd historical average, which led to a decrease in nitrogen excretion and waste.

The study concluded amino acid balancing can effectively maintain and even improve performance, while reducing the need to overfeed protein, a win-win for both the dairy producer and the environment.

Feed the right amino acid sourceWhen it comes to amino acid balancing, both the quality and quantity of lysine and methionine count. Many dairies today feed commodity blood meal in an attempt to supply optimal levels of lysine to the diet. Research conducted by Marshall Stern, PhD at the University of Minnesota2 and Normand St-Pierre, PhD, at The Ohio State University3 found lysine levels in blood meal to be extremely variable and inconsistent. Day-to-day variability in the nutrients delivered in blood meal can negatively impact cow performance and production.

Delivering consistent levels of lysine to the small intestine can translate to improved feed efficiency, nutrient utilization and production and, ultimately, greater milk check profits.